Envirogen Leadership Team

Joe Higgins, Group Chief Executive Officer

Joining Envirogen in 2021 following a 25-year career in the water, energy, and hazardous waste industry, Joe is Group CEO and CEO for North America. Joe has overall responsibility for operations in North America, the UK, and Europe, as well as strategic planning and growth initiatives.

He is committed to sustainably growing the organisation through synergetic strategic partnerships and delivering innovative, competitive, and sustainable solutions for our customers.

Martin Holt, Group Finance Director

Martin joined Envirogen in early 2024. His role as Group Finance Director provides a vital link between the Envirogen Group, its North American sister company, Envirogen Technologies Inc. and key stakeholders.

With a proven history of navigating complex financial landscapes and implementing impactful solutions, Martin is adept at driving positive change. He has expertise in managing businesses of varying sizes and spearheading major financial initiatives.

James Hepton, Group Marketing Director

James joined Envirogen in early 2022 and is responsible for marketing activities across the Group business. James has run marketing departments for both SMEs and large businesses at a senior level across numerous industries, including electronics, telecoms, manufacturing and construction, focusing on improved efficiency and performance with internal and external marketing resources and delivering a solid return on marketing spend.

James believes in presenting consistent, quality branding across the organisation and using technology and innovation to demonstrate our capabilities and communicate with our customers.

Scott Malvenan, Group Non-Executive Chairman

Scott has extensive experience in the construction, electronics, textiles, furniture and water engineering industries. He was previously CEO of Envirogen Group from 2017 to 2021 and is now Group Non-Executive Chairman.

Scott has a strong focus on building shareholder value, creating sustainable competitive advantage and exceeding customers’ expectations. He has experience in significant change management, and financial and operational performance gained in international markets in varied ownership structures, including plc, joint venture, private equity, and other financial institutions.

Mike Stark, Chairman, North America

Mike Stark is the Chairman of our North American business. He was one of the Founders of Envirogen Technologies Inc., in October 2009, which is now Envirogen Group, LLC. Prior to Envirogen Mike was President and CEO of Veolia Water North America and before that, he was President of US Filter Operating Services Inc.

He began his career in 1965 and was one of the original members of Calgon Adsorption Systems which became Calgon Carbon, Inc. Mike believes a Solution Provider should be willing to warranty the performance, reliability and operating expectations associated with the projects it performs.

Dr. Silvia Santana, Chief of Staff

A strategic innovator and trusted advisor, Dr. Santana brings a proven record of driving growth through disciplined project execution and high-impact relationship building across global organizations.

Dr. Santana holds a Doctorate in Leadership and Administration, alongside advanced degrees in Business Ethics and Communications. Silvia works with executive leadership teams to accelerate strategic priorities and strengthen organizational performance. Her expertise in change leadership is vital to our business as we enter the next stages of growth.

RajaVenkat Beereddy, VP PMO & Engineering

Raj joined Envirogen in 2026 and leads Engineering and Project Management for North America. He brings hands‑on experience across engineering, fabrication, procurement, project management, quality control, and operations, having built and led multiple functions at leading water treatment companies.

Raj’s career spans senior leadership roles in municipal, industrial, and nuclear water, wastewater, and waste treatment sectors. He is committed to disciplined execution, quality outcomes, transparency, and consistently delivering on customer commitments.

Tim Metcalfe, Chief Operating Officer UK & EU

As Chief Operating Officer, Tim uses his extensive experience and expertise to drive the UK and EU businesses forward and assist in driving key initiatives.

Previously, Tim was the Group Finance Director for the Envirogen Group for 7 years and prior to that he qualified as a Chartered Accountant, had 12 years at KPMG and then a further decade of Board experience across a range of industries.

Bill Denyer, Chief Revenue Officer

Bill has over 25 years’ of experience in the water treatment industry. After initially starting with GE within the mobile water sector he went on to work on the installation and commissioning of build own operate maintain systems before starting his first role with Envirogen as Process & Systems specialist.

During the initial period of his Envirogen career Bill specialised in the brewing and soft drinks industries while developing a detailed understanding of hollow fibre membrane applications as he supported clients across multiple continents. In recent years Bill took his experience into the Commercial arm of the Envirogen Group before moving on to the Executive team during 2018.

Ross Dummett, Group Contracts Director

Ross joined Envirogen in late 2022 following a 30-year career in design and build contracting across Water (municipal and industrial), Water recycling, Energy, Solid Waste and Civil Engineering.

Ross is the Group Contracts Director with responsibility for the Project Management Office (PMO) and Engineering in the UK, including supporting the North American business. Passionate about projects, he is committed to the right-first-time mantra to deliver positive outcomes for our customers and end users.

Bart Scholten, Group Business Development Manager – PLF

Having spent over 30 years designing and delivering process filtration projects, Bart is a world-leading specialist, often speaking at key industry events.

As Group Business Development Manager, he focuses on growing the process filtration business with a focus on pressure leaf applications. Bart supports the sales team through development and coaching so they can provide optimal solutions for clients.